A claim for priority for this application is made under Japanese Application JP H10-353,078.
1. Field of the Invention
The present invention relates to an inductor having a high Q value for use in high frequency in a semiconductor integrated circuit (IC).
2. Description of the Related Art
A conventional inductor will be described with reference to FIG. 9. Referring to FIG. 9, the reference numeral 1 denotes an inductor section, 2 denotes a drawing interconnect formed in the first layer, 3 denotes a drawing interconnect formed in the second layer, 5 denotes a connection between the first and second layers, 7 denotes an interlayer film, and 8 denotes a smoothing film.
That is, in the conventional inductor, the inductor section is constructed of a single layer and the second layer is used for the drawing interconnect for connection with other components.
As one of characteristics of an inductor, it is generally known that in order to obtain a large inductance value, the line length of the inductor must be increased.
With the above conventional construction, however, when the line length is increased in order to obtain a large inductance value, the serial resistance component increases due to the resistance of a wiring material constituting the inductor, resulting in lowering the Q value of the inductor.
Further, the increased line length of the inductor tends to increase the size of the entire inductor.
In view of the above problems, an object of the present invention is to provide an inductor having a high Q value while suppressing the serial resistance from increasing.
Another object of the present invention is to provide an inductor of which size is not increased even when the line length thereof is increased.
A high-Q inductor for high frequency of the first present invention is such inductor that one inductor has a plurality of inductor elements formed in a plurality of IC wiring layers respectively, and the directions of magnetic fields generated by the respective inductor elements are substantially the same.
A high-Q inductor for high frequency of the second present invention according to the first present invention, is such inductor that the plurality of inductor elements are connected in series.
A high-Q inductor for high frequency of the third present invention according to the first present invention is such inductor that the plurality of inductor elements are connected in parallel.
A high-Q inductor for high frequency of the fourth present invention according to the first present invention, is such inductor that the plurality of inductor elements include a serial-connected circuit portion and a parallel-connected circuit portion.
A high-Q inductor for high frequency of the fifth present invention according to the first present invention, is such inductor that at least one of the inductor elements is in a meander shape or a spiral shape.
A high-Q inductor for high frequency of the sixth present invention according to any one of the first to fifth present inventions, is such inductor that a connection between the plurality of inductor elements is formed in an interlayer film disposed between the IC wiring layers in which the inductor elements are formed.
A high-Q inductor for high frequency of the seventh present invention according to the first present invention is such inductor that a drawing interconnect from the inductor element is formed in the IC wiring layer in which one of the inductor elements is formed.
The senventh present invention corresponds to FIG. 1.
A high-Q inductor for high frequency of the eighth present invention according to the seventh present invention is such inductor that the plurality of inductor elements are in a spiral shape respectively and connected in parallel with each other, and one of the drawing interconnect is connected to a spiral center of the inductor element and drawn externally by being formed in one of the IC wiring layers, and
the spiral-shaped inductor element formed in the IC wiring layer used for the external drawing is cut off at positions where the drawing interconnect crosses, and cut-off ends of the inductor element are connected with each other by being connected with respective corresponding portions of the spiral-shaped inductor element formed in another one of the IC wiring layers.
The eighth present invention corresponds to FIG. 3.
A high-Q inductor for high frequency of the ninth present invention according to any one of the first to sixth present inventions is such inductor that a drawing interconnect from the inductor element is formed in a wiring layer which is different from the IC wiring layers in which the inductor elements are formed.
The ninth present invention corresponds to FIG. 2.
A high-Q inductor for high frequency of the tenth present invention according to the ninth present invention, is such inductor that a drawing interconnect and the inductor element to be connected with the drawing interconnect are connected via an connection formed in an interlayer film disposed between a wiring layer in which the drawing interconnect is formed and the IC wiring layer in which the inductor element is formed.
The tenth present invention corresponds to FIG. 2.
A high-Q inductor for high frequency of the eleventh present invention according to the first present invention, is such inductor that the plurality of inductor elements are in a spiral shape respectively,
adjacent inductor elements of the plurality of inductor elements are connected with each other in such manner that the adjacent inductor elements are serially connected by connecting the spiral centers thereof with each other and outer ends thereof with each other,
spiral directions of the adjacent inductor elements are in reverse from each other, and
directions of the magnetic fields generated by the respective inductor elements are substantially the same.
The eleventh present invention corresponds to FIG. 4 and FIG. 5.
A high-Q inductor for high frequency of the twelfth present invention according to the first present invention, is such inductor that the plurality of inductor elements are in a spiral shape respectively,
the plurality of inductor elements are alternately connected with each another in such manner that the inductor elements are serially connected by connecting the centers thereof with each other and outer ends thereof with each other,
the spiral directions of adjacent inductor elements repeats the same and the reverse in order, and
the directions of the magnetic fields generated by the respective inductor elements are substantially the same.
The twelfth present invention corresponds to FIG. 6